Python 字符串比较

Question

我有一个 python 函数，它对输出“true”或“false”的 shell 脚本进行子进程调用。我正在存储 subprocess.communicate() 的输出并尝试执行 return output == 'true' 但它每次都返回 False .我对 python 不太熟悉，但是阅读有关字符串比较的文章说您可以使用 ==、!= 等来比较字符串。

代码如下:

def verifydeployment(application):
    from subprocess import Popen, PIPE
    import socket, time

    # Loop until jboss is up.  After 90 seconds the script stops looping; this
    # causes twiddle to be unsuccessful and deployment is considered 'failed'.
    begin = time.time()
    while True:
        try:
            socket.create_connection(('localhost', 8080))
            break
        except socket.error, msg:
            if (time.time() - begin) > 90:
                break
            else:
                continue

    time.sleep(15)  # sleep for 15 seconds to allow JMX to initialize

    twiddle = os.path.join(JBOSS_DIR, 'bin', 'twiddle.sh')
    url = 'file:' + os.path.join(JBOSS_DIR, 'server', 'default', 'deploy', os.path.basename(application))

    p = Popen([twiddle, 'invoke', 'jboss.system:service=MainDeployer', 'isDeployed', url], stdout=PIPE)
    isdeployed = p.communicate()[0]

    print type(isdeployed)
    print type('true')
    print isdeployed
    return isdeployed == 'true'

输出是:

<type 'str'> # type(isdeployed)
<type 'str'> # type('true')
true         # isdeployed

但是总是返回False。我还尝试了 return str(isdeployed) == 'true'。

Answer 1

您确定没有终止换行符，使您的字符串包含 "true\n" 吗？这似乎很有可能。

您可以尝试返回 isdeployed.startswith("true")，或进行一些剥离。